Smelting Recipes
This can add vanilla furnace smelting recipes:
smelt: {stackref} => {stackref} [ * {number} ] [ + {xp} xp ]
The output number will default to 1 if not specified
XP will default to 0 if not specified
// Will smelt a gold ingot to 2 diamonds and give 100 xp smelt: I:gold_ingot => I:diamond * 2 + 100 xp